Blade for ceiling fans

ABSTRACT

A blade for ceiling fan consists of a frame and a blade body. The frame is made by plastic injection forming process or metal die casting, and includes two half sections to form a male element and a female element. The frame has a blade body holding means and an anchoring means to hold and anchor the blade body securely on the frame. The frame has a greater thickness than the blade body.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to an improved blade for ceiling fans and particularly to a blade that has a frame made by injection or die casting forming process to couple with an extensible blade body to form an integrated blade structure.

[0003] 2. Description of the Prior Art

[0004] Conventional ceiling fans generally have blades made from plywood or woods. Fabrication of wooden blades requires many different processes, including cutting, trimming, patching, multiple surface polishing, periphery trimming, painting, or surface coating. More than twenty different fabrication processes could be involved. Finally, three or four pieces of blades are selected and grouped, and weighed for final packaging. The fabrication processes are tedious and labor-intensive. As a result, blades for ceiling fans are high cost products. How to simplify assembly operations and reduce costs have become important research and development issues for producers.

SUMMARY OF THE INVENTION

[0005] Therefore the primary object of the invention is to resolve aforesaid disadvantages that incur to fabrication processes. The invention provides an improved blade structure for ceiling fans that has a frame made by injection or die casting forming process and a blade body made from an extensible material such as fabrics, paper, thin metal sheets or plastics, and can be made and assembled rapidly with less labor, and eliminates the costly and time-consuming fabrication processes incurred to conventional techniques.

[0006] Another object of the invention is to provide blades each has a weight within an allowable range after assembling such that weight measuring and grouping operations before packaging are much simpler and productivity can be increased and product defects resulting from not conforming to specifications can be reduced.

[0007] A further object of the invention is to provide a frame made from plastic injection forming process or aluminum alloy die casting to facilitate mass production, and with blade bodies that can be printed with patterns desired and may be cut and trimmed by machines in high speed, and may be assembled by specialized assembly machinery in the plant, or subcontract to outside fabrication, thereby can greatly increase production efficiency and save manpower and reduce production costs.

[0008] Yet another object of the invention is to provide a blade that is weighed about 40% to 50% of a conventional wooden blade therefore motor power for driving the blade can be reduced proportionally, and costs of the blade and motor can also be reduced, thereby enables the resulting ceiling fans to have high competitiveness in the global market.

[0009] In order to achieve the foregoing objects, the frame of the invention is formed in a hollow and annular cross section, and consists of two half sections made by plastic injection or die casting forming process. One half section is a male element and another half section is a female element. The male element and the female element may be coupled together to form a hollow blade frame with patterns printed thereon. The frame has one end with a larger solid section to serve as an anchoring end. The blade body is made from a piece of plastic sheet, leather or fabrics with printing patterns and is cut to the shape of the frame but in a smaller size. The frame has a blade body holding means located on the male or female element to hold the blade body before assembly to facilitate later on assembly operation, and an anchoring means located respectively on the male element and the female element for coupling the two together and to fasten the blade body firmly therebetween. The blade body is held by the blade holding means between the male element and the female element, then the male element and the female element are coupled together to clip the blade body therebetween. The blade thus formed has a frame thicker than the blade body.

[0010] The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is a perspective view of a blade of the present invention;

[0012]FIG. 2 is an enlarged plan view of an embodiment of a female element of the present invention;

[0013]FIG. 3 is a cross section taken along line A-A in FIG. 1 showing the male and female element;

[0014]FIG. 3A is a cross section of another embodiment according to FIG. 3;

[0015]FIG. 3B is a cross section of yet another embodiment according to FIG. 3;

[0016]FIG. 3C is a cross section of still another embodiment according to FIG. 3;

[0017]FIG. 4 is a cross section taken along line B-B in FIG. 1;

[0018]FIG. 4A is a cross section of another embodiment according to FIG. 4;

[0019]FIG. 4B is a cross section of yet another embodiment according to FIG. 4;

[0020]FIG. 5 is a fragmentary exploded view of another embodiment of an anchoring means located on the male and female elements; and

[0021]FIG. 6 is a cross section taken along line C-C in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Referring to FIGS. 1, 2, and 3, the improved blade for ceiling fans according to the invention consists of a frame 1 and a blade body 2. The frame 1 is a hollow tubular member made from high strength plastics such as ABS and the like by injection forming process, or made from aluminum by die casting. The frame includes two half sections. One half section is a male element 11 and another half section is a female element 12. The male element 11 and the female element 12 may be coupled together to form the hollow frame 1. The frame 1 has one end with a larger solid section to serve as an anchoring end 1A (referring to FIG. 1) for fastening to the bracket of a ceiling fan. The blade body 2 may be made from plastic sheets, cloths, paper, thin metals or fabrics that are printable and readily available on the market. The blade body 2 is formed in a shape similar to the frame 1 but with a smaller periphery, and has a plurality of anchoring holes 21 formed on the peripheral rim thereof in an equally spaced fashion. The blade body 2 may be clipped between the male element 11 and the female element 12 to form a complete frame with a thicker frame 1 surrounding a thinner blade body 2.

[0023] As previously discussed, the frame 1 of the invention is not made from woods, but is made by plastic injection forming or aluminum die casting in mass production processes. In order to facilitate clipping of the blade body 2 in the frame 1, the frame 1 is designed and formed by coupling the male element 11 with the female element 12. The male and female elements have respectively an anchoring means to clip and fasten the blade body 2. FIG. 3 shows a first embodiment of the anchoring means. On the inner wall of the female element 12, there are a plurality of vertical wedge hollow struts 121 located thereon in an equally spaced manner. The female element 12 has two lateral sides forming respectively an annular shoulder rim 122 adjacent to a jutting rib 123. The male element 11 has wedge bores 111 formed on locations corresponding to the hollow struts 121, and may receive tap screws 13 to form a secured fastening with the wedge hollow struts 121. The male element 11 also has two lateral sides forming respectively an annular jutting flange 112 and an indented shoulder 113 corresponding to the annular shoulder rim 122 and the jutting rib 123 of the female element 12. As shown in FIGS. 3 and 4, the anchoring holes 21 of the blade body 2 may be engaged with the wedge hollow struts 121 of the female element 12 before the male element and the female element are assembled so that the blade body 2 may be held by the female element 12 without dislocation when the male element 11 is coupled with the female element 12. Thus the wedge hollow struts 121 of the female element 12 also function as a holding means for the blade body 2.

[0024] Referring to FIGS. 3 and 4, during assembly, couple the anchoring holes 21 of the blade body 2 with the wedge hollow struts 121 of the female element 12, then clip the blade body 2 with the male element 11, and couple the male element 11 with the female element 12. As the blade body 2 is laid over the female element 12, the male element 11 cannot form a complete sealing with the female element 12, therefore the tap screws 13 may be employed to run through the wedge bores 111 and engage with the wedge hollow struts 121 to form a firm and secure fastening. The jutting flange 112 and rib 123, and the indented shoulder 113 and shoulder rim 122 of the male and female elements may clamp the blade body 2 to form a zigzag clipping on the peripheral edges (as shown in FIGS. 3 and 4 on the left hand side). Such a construction enables the blade body 2 to be automatically clamped and stretched tightly from all directions when the male and female elements are coupled and fastened together. The resulting blade body has an even and smooth surface. In this embodiment, the annular jutting flange and rib, and the indented shoulder and shoulder rim on the male and female elements become a blade body tightening means.

[0025] The two half-section construction for the frame set forth above, and the production method of plastic injection forming or aluminum alloy die casting also can enhance product quality at a consistent level. To facilitate production, an assembly jig may be made to match the wedge bores 111 of the male element 11 for holding multiple number of tap screws 13, and a plurality of electric drivers may be disposed over the tap screws 13, then the jig may be lowered upon male element 11 and over the female element 12 for driving the tap screws 13 simultaneously into the wedge hollow struts 121 to accomplish fast assembly.

[0026] Fastening without utilizing tap screws can also be done. FIG. 3A shows such an approach. The previous wedge bores 111 in the male element 11 are changed to become pins 114 each has an elastic slit 115 formed in the center. The outer diameter of the pin 114 is slightly larger than the inner diameter of the hollow struts 121. The pins 114 may be inserted into the hollow struts 121 by force through a hydraulic press such that the elastic slit 115 is squeezed in the interior of the hollow strut 121 to form a tightly engagement between the pin 114 and the hollow strut 121. In this embodiment, the pins 114 and the hollow struts 121 are the anchoring means.

[0027]FIGS. 4A and 4B illustrate other possible structures of the tightening means. In FIG. 4A, in addition to the indented shoulder 113, shoulder rim 122, and jutting flange 112 and rib 123 on the peripheral rim of the male element 11 and female element 12, the inner wall of the male element 11 has a vertical wedge jutting ridge 116 extending towards the female element 12, and the female element 12 has a wedge trough 124 located on the inner wall matching the jutting ridge 116. Hence when the male element 11 and the female element 12 are coupled together, the peripheral edge of the blade body 2 is clamped in an inverse Ω shape to further tighten the blade body 2. FIG. 4B shows another approach which is an alteration of the one shown in FIG. 4A. Instead of forming an inverse Ω shape clipping on the blade body 2, a double L-shaped clipping is formed on the blade body 2. In the event that the inverse Ω shape clipping or double L-shaped clipping produces too much surface tension on the blade body 2, the surface tension may be reduced by shrinking the sizes of the indented shoulder 113, shoulder rim 122, and jutting flange 112 and rib 123. Or the indented shoulder 113, shoulder rim 122, and jutting flange 112 and rib 123 are totally omitted, and the peripheral rims of the male and female are formed in flat surfaces to make plane contact and connection. The selections may be made based on materials and thickness of the blade body 2. The techniques for design of the jutting and indented sections are known in the art, details are omitted here.

[0028]FIG. 3B shows another embodiment of the structure of the male element 11 and the female element 12. The female element 12, besides having the shoulder rim 122 and jutting rib 123 formed on the peripheral rim and hollow struts 121 in the center, also has an annular and vertical jutting ridge 125 formed between the hollow struts 121 and the peripheral rim; and the male element 11 besides having the jutting flange 112 and indented shoulder 113 on the peripheral rim and pins 114 in the center, also has an annular indented ditch 117 formed between the pins 114 and the peripheral rim corresponding to the jutting ridge 125 of the female element 12. Thus when the male element 11 and the female element 12 are coupled, and the pins 114 are inserted into the hollow struts 121, the annular jutting ridge 125 of the female element 12 is inserted into the annular ditch 117 of the male element 11. During assembling of the blade body 2, first engage the anchoring holes 21 of the blade body 2 with the pins 114 of the male element 11 and cover the entire male element 11 with the blade body 2, then place the female element 12 over the male element 11, and wedge the annular jutting ridge 125 into the annular ditch 117. As the ditch 117 has a desired depth, when the female element 12 and the male element 11 are coupled, substantial peripheral length of the blade body 2 will be pulled and wedged into the ditch 117 to form a tightly fastening. Thus the blade body 2 and the male element 11 and the female element 12 may be formed an integrated member with tightly coupling. Such a construction is simpler, and assembly can be done quickly, and the blade body 2 can also be tightened at the same time. The invention thus offers a significant improvement for production.

[0029] When there is a desire to further enhance the fastening of the blade body 2 to the frame 1, another embodiment may be adopted as shown in FIG. 3C. In addition to the annular jutting ridge 125 on one side of the female element 12, a second annular jutting ridge 125′ may be formed on another side thereof. And the male element 11 also has a second annular ditch 117′ formed on another side to match the second annular jutting ridge 125′. Such a construction can securely tighten the blade body 2 on the frame 1 without loosening or breaking away. The root section of the blade of the invention adopts three screws to fasten to the blade bracket (not shown in the drawings) like conventional techniques do. As shown in FIGS. 2 and 6, the root section has a larger solid section, in order to reinforce the supporting mechanical strength, two jutting ridges 126 and 126′ may be formed thereon in a cross fashion. In addition, two arch-shaped reinforced jutting ridges 127 and 128 may be formed around the periphery of the cross ridges 126 and 126′. On the root section for fastening to the blade bracket, three apertures 14 are formed. Each aperture 14 is formed by a hollow pin 141 extending from the male element 11 and a matching hollow strut 142 located on the female element 12. The aperture 14 may receive a screw to engage with a screw nut to securely fasten the frame to the fan bracket.

[0030]FIG. 5 illustrates another embodiment for the anchoring means. The inner jutting rib of the female element 12 may have cavities 129 formed thereon in an equally spaced manner, and the outer shoulder rim of the female element 12 may have notches 129′. The male element 11 may have bulged spots 118 on the inner flange and jutting stubs 118′ on the outer indented shoulder corresponding respectively to the cavities 129 and notches 129′ of the female element 12. The blade body 2 also round apertures 22 and notches 23 formed by punching to match respectively with the bulged spots 118 and jutting stubs 118′. Hence the bulged spots 118, pins 114 and jutting stubs 118′ of the male element 11 may be coupled with the cavities 129, hollow struts 121 and notches 129′ of the female element 12 through the round apertures 22 and notches 23. Then the spots 118 and the coupling cavities 129, and the stubs 118′ and the coupling notches 129′ may be hot melted together to form a strong bonding by means of supersonic or high frequency bonding means. The pins 114 and hollow struts 121 may also be hot melted together if desired. Thus the frame 1 and the blade body 2 may be bonded to form a very strong binding. When the blade body 2 and the frame 1 are made from different materials, spot hot melt could be not effective to bond the blade body 2 and the frame 1 together. In such a circumstance, the inner and outer rims of the male element 11 and female element 12 may be bonded by hot melt. Another approach is to tighten the blade body 2 on the frame 1 as shown in FIGS. 3, 3A, 4, 4A or 4B, then apply equally spaced spot hot melt or entire hot melt to bond the frame. Whichever approach is desirable depends on material properties of the male element, the female element and the blade body, and dimensions thereof, and cost considerations. These techniques are known in the art, thus details are omitted here.

[0031] In summary, the invention provides a frame and a blade body that are made separately, then are assembled together. The frame has anchoring means, blade body holding means and tightening means. The structure is simpler, production is faster, costs are lower, and product defects can be reduced. Production process can be simplified and problems incurred to the complex fabrication processes of conventional techniques can be overcome.

[0032] While the preferred embodiments of the invention have been set forth for the purpose of disclosure, modifications of the disclosed embodiments of the invention as well as other embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments which do not depart from the spirit and scope of the invention. 

What is claimed is:
 1. A blade for ceiling fans, comprising: a frame including two half sections, one half section forming a male element and another half section forming a female element for coupling together to form the frame, the frame being hollow and formed substantially in an annular shape with one end having a larger solid section serving as an anchoring end to fasten to a ceiling fan bracket; a blade body having a shape substantially matching the frame but having a smaller size than the frame; a blade body holding means selectively located on the male element or the female element for holding the blade body before assembling of the male element and the female element and facilitating the assembling thereafter; and an anchoring means located respectively on the male element and the female element for fastening the blade body to a middle portion of the frame during the assembling.
 2. The blade for ceiling fans of claim 1, wherein the blade body holding means includes a plurality of vertical pins extending from an inner wall of the male element in an equally spaced fashion, and a plurality of vertical wedge hollow struts extending from an inner wall of the female element in an equally spaced fashion, and the pins and the wedge hollow struts being corresponding to a plurality of anchoring holes formed on the peripheral rim of the blade body.
 3. The blade for ceiling fans of claim 1 further having a blade body tightening means located between the frame and the blade body for stretching the blade body evenly to form a smooth surface when the peripheral rim of the blade body is clamped and fastened between the male element and the female element.
 4. The blade for ceiling fans of claim 1, wherein the anchoring means includes a plurality of vertical wedge hollow struts extending from an inner wall of the female element in an equally spaced fashion, a plurality of equally spaced wedge bores running through the male element corresponding to the wedge hollow struts and a plurality of tap screws running through the wedge bores to engage with the wedge hollow struts for fastening the male element to the female element.
 5. The blade for ceiling fans of claim 1, wherein the anchoring means includes a plurality of vertical wedge hollow struts extending from an inner wall of the female element in an equally spaced fashion, a plurality of pins extending from an inner wall of the male element in an equally spaced fashion corresponding to the wedge hollow struts, each of the pins having a slit and an outer diameter greater than the inner diameter of the wedge hollow strut such that the pins are inserted into and engaged and with the wedge hollow struts when the male element and the female element are coupled together.
 6. The blade for ceiling fans of claim 3, wherein the blade body tightening means includes an annular jutting flange and an annular indented shoulder formed on the peripheral rim of the male element, and an annular shoulder rim and an annular jutting rib formed on the peripheral rim of the female element matching complementarily and geometrically the annular jutting flange and the annular indented shoulder of the male element to clip and stretch the blade body in radial directions.
 7. The blade for ceiling fans of claim 3, wherein the blade body tightening means includes an annular wedge jutting ridge extending from an inner wall of the male element towards the female element, and an annular wedge trough extending from an inner wall of the female element towards the male element for coupling with the wedge jutting ridge of the male element.
 8. The blade for ceiling fans of claim 3, wherein the blade body tightening means includes at least one annular jutting ridge extending respectively from an inner wall of the male element and from the inner wall of the female element towards each other in a staggered manner to form a firm latching condition.
 9. The blade for ceiling fans of claim 2, wherein the female element has at least one annular vertical jutting ridge located between the hollow struts and an inner peripheral rim thereof, and the male element has an annular indented ditch formed on an inner peripheral rim thereof corresponding to the annular jutting ridge such that after the anchoring holes on the peripheral rim of the blade body being coupled with hollow struts of the female element, the male element and the female element being allowed to couple together and to clip the peripheral rim of the blade body between the annular jutting ridge and the annular indented ditch to fasten and stretch the blade body to form a tight tension on the surface of the blade body.
 10. The blade for ceiling fans of claim 9, wherein at least one annular indented ditch is formed on the female element and at least one annular jutting ridge is formed on the male element.
 11. The blade for ceiling fans of claim 1, wherein the anchoring means further includes a plurality of bulged spots formed on an inner peripheral rim and a plurality of jutting stubs formed on an outer rim of the male element, and a plurality of cavities formed on an inner peripheral rim and a plurality of first notches formed on an outer rim of the female element corresponding respectively to the bulged spots and the jutting stubs, and the blade body having round apertures and second notches formed on the peripheral rim thereof corresponding respectively to the bulged spots and the jutting stubs of the male element such that the bulged spots and the jutting stubs of the male element being allowed to run through the round apertures and the second notches to couple with the cavities and the first notches of the female element, and after the pins of the male element being inserted into the wedge hollow struts of the female element, the coupled bulged spots and the cavities, and the coupled jutting stubs and the first notches being hot melted together by means of a supersonic means.
 12. The blade for ceiling fans of claim 11, wherein the hot melted is done by a high frequency means.
 13. The blade for ceiling fans of claim 2, wherein the pins of the male element are coupled with the corresponding wedge hollow struts of the female element, and the coupled pins and wedge hollow struts being hot melted together by a supersonic means.
 14. The blade for ceiling fans of claim 2, wherein the pins of the male element are coupled with the corresponding wedge hollow struts of the female element, and the coupled pins and wedge hollow struts being hot melted together by a high frequency means.
 15. The blade for ceiling fans of claim 11, wherein the male element and the female element are coupled through peripheral rims thereof, and the coupled peripheral rims being hot melted together by a supersonic means.
 16. The for ceiling fans of claim 11, wherein the male element and the female element are coupled through peripheral rims thereof, and the coupled peripheral rims being hot melted together by a high frequency means.
 17. The blade for ceiling fans of claim 1, wherein the frame is fastened to the ceiling fan bracket through an aperture formed in the frame, the aperture being formed by a hollow pin located on the male element coupling with a hollow strut located on the female element.
 18. The blade for ceiling fans of claim 1, wherein the blade body is selectively formed by plastic injection forming process or metal die casting.
 19. The blade for ceiling fans of claim 1, wherein the blade body is made from a material selecting from the group consisting of plastic sheets, leather, paper, thin metals or fabrics. 